Control apparatus for polyphase systems



Feb. 21, 1950 WINTHER 2,498,057

CONTROL APPARATUS FOR POLYPHASE SYSTEMS Original Filed May 4, 1944Patented F eb. 21, 1950 CONTROL APPARATUS FOR POLYPHASE SYSTEM AnthonyWinther, Kenosha, Wis., Martin P. Winther, Waukegan,

Original application Ma assignor to 111., as trustee y 4, 1944, SerialNo. Divided and this application March 20, 1946, Serial No. 655,699

2 Claims. (01. 171-97) This invention relates to control apparatus forpolyphase systems, and with regard to certain more specific features, toa voltage control.

This application is a division of my United States patent applicationSerial No. 534,111, filed May 4, 1944, for Electronic control apparatus,issued as Patent 2,469,706, dated May 10, 1949.

Among the several objects of the invention may be noted the provision ofmeans for producing a voltage in response to current in a multi-phase A.C. circuit supplying an A. C. motor under variable load such that thevoltage will be proportional to motor torque. Other objects will be inpart obvious and in part pointed out hereinafter.

The invention accordingly comprises the elements and combinations ofelements, features of construction, and arrangements of parts which willbe exemplified in the structures hereinafter described, and the scope ofthe application of which will be indicated in the following claims.

In the accompanying drawing, in which is illustrated one of variouspossible embodiments of the invention,

The single figure is a wiring diagram of the connections required forthe invention.

Referring now more particularly to the drawing, T-S indicates atransformer and WM an A. C. motor. The primary of the transformer T-B isenergized from an A. C. circuit through provide a voltage which issubstantially a straight-line function of the torque delivered by the A.C. motor WM. This is accomplished by means of a current trans formerT-HJ having a primary in the line L3 and a secondary which feeds theprimary of the transformer T- Q. Thus transformer T40 is in one phase ofthe multi-phase A. C. circuit L-l, L4, L4. Resistance R-l5 is connectedacross the secondary of the transformer T-lfl. This provides a load.

A voltage transformer T Il connected across the lines L-I A. C. circuit.Thus it is connected across another phase of the A. C. circuit.Resistance R-l3 forming a resistance load and first potentiometer hasits primary and Ir-2 of the Point 34 of transformer T-H is connected tothe variable tap 32 of a third resistance load R-I2 which acts as asecond potentiometer. By a suitable adjustment of the resistances R42and R-l3, the transformer T-I I can be caused to buck down suchcomponent of current generated in the transformer T-IO as is caused bythe magnetizing requirements of the motor WM. The transformer T-ll is soconnected, and 32 and 33 are so adjusted, that the voltage generated byT-H cancels the voltage generated by the transformer T-Hl when the motoris idling. Resistances R-l 2, R-l 3 and R-I 5 are series connected.

circuit between transformers T-9, T-IU and T-H may be referred to as atransformer circuit for obtaining a straight-line relationship betweenthe voltage on T-9 and torque on the motor WM. Potentiometer R-l3 is theone that bucks out ondary voltage the motor is idling.

r 3 series-connected resistance loads respectively fed by thesecondaries of said transformers, the resistance connected with thevoltage transformer constituting a first potentiometer, a thirdresistance load connected in series with said two resistance: loads andfconstituti-ng aassecorid potentiometer and supplying a circuit whichis'to be controlled, said first potentiometer being adjusted so that thesecondary voltage of said voltage transformer bucks out substantially;all of-the secondary voltage of said current transformer when the motoris idling, said second potentiometer controlling the slope of-theresi'lltingestraightv line relationship between the contr'dlledwoltagein said controlled circuit and: thercurrentzin said 15 A. C. circuit.

ANTHONY WINTI-IER.

REFERENCES CITED The following references are of record in the file ofthis patent:

';Number Number UNITED STATES PATENTS Name Date Seeley Aug. 22, 1933MacKay Dec. 14, 1943 Lewis Sept. 3, 1946 FOREIGN PATENTS Country DateGreat Britain Oct. 24, 1929 ,France Mar. 20, 1917

